This invention relates to continuous motion article packaging machines, such as used in the bottling industry to package pre-formed bottle groups into paperboard cartons or carriers. More particularly, this invention relates to a carton flap folding method and apparatus suited for use in a continuous motion packaging machine. The method and apparatus of the present invention, however, have applications in other environments requiring the manipulation of a workpiece into a desired orientation.
Continuous motion article packaging machines, such as those used in the beverage packaging industry, are well known in the art. These machines typically include numerous workstations arranged sequentially along a conveying system, such as chain or belt conveyors. Such packaging machines include carton feeders for delivering collapsed paperboard cartons or carton blanks to a carton conveyor, article grouping mechanisms which arrange articles, such as beverage containers or bottles, into desired configurations, and packaging assemblies which place the articles into the carton and secure or close the carton. These operations occur continuously and at relatively high speeds, typically packaging the article groups at a rate of 150 packs per minute to 400 packs per minute, and higher.
During various stages of this process, the cartons or carton blanks are handled in a variety of ways. The cartons usually are supplied to the packaging machine by the carton feeder, which selects cartons one at a time from a carton supply magazine, and places the cartons onto the carton conveyor. Numerous different types of cartons are utilized in these operations, including wrap-type carton blanks, basket-type cartons having an open bottom wall, basket-type cartons having a closed bottom wall and sleeve-type cartons, including those with tapered side portions. These cartons require various different handling procedures, including placing the carton in a specific orientation as it proceeds downstream, folding pre-formed carton flaps and bringing opposed or adjacent carton portions into contact with one another to lock carton side walls or bottom walls together to complete the packaging operation.
The large variety of cartons have various characteristics which must be taken into account during the packaging operation. These characteristics include, for example, different sized flaps, score lines, handles, locking tabs, cut-out portions and webbing or gussets. When packaging articles in sleeve-type cartons, the sleeve typically is fed downstream in a collapsed or flattened state, and thereafter must be erected so that the opposed sidewalls are spaced from one another to form an interior, open area into which the articles are inserted. In erecting the carton using mechanical cams or vacuum assisted devices, the lower sidewall of the carton sleeve can be engaged and held against the conveyor or score rails, while the opposed, upper sidewall is raised. One common way of holding the lower sidewall during this step is to engage the carton""s lower, major flaps with a fixed guide while the carton moves downstream, so that the carton is not lifted from the conveyor during the step of erecting the carton. In order to engage the carton""s lower, major flaps, the flaps are directed below opposed guides or guide plates positioned on each side of the conveyer and extending a distance, for example approximately three feet, along the carton conveyor. The lower, major flap is caused to move downwardly in order to slide below the flap guides, while the carton is being moved in the downstream direction by the carton conveyor.
In the past, this flap folding step has been accomplished by using mechanical devices such as a cam or a pneumatic flap knocker, which contact the flaps, and with a camming surface, causes the flaps to move into a lowered position so that the flaps slide below the guides as the conveyor moves the carton downstream. The guide holds the flaps and the carton""s lower sidewall which is attached to the flaps, in a fixed vertical position as the carton is continuously moved downstream. These prior devices, however, often require that the lower, major flap be independently accessible, that is not covered entirely by the upper, major flap, as it moved through the packaging machine, either by the design of the flaps, in which the lower, major flap extends beyond the upper, major flap, or with the use of a cut-out portion in the upper, major flap, to allow the mechanical element to contact the lower flap, only, and move the lower flap beneath the guide. Such carton designs, however, can adversely affect the carton""s manufacture, or the appearance or function of the fully formed package. Therefore, it is desirable in many cases to avoid the use of cutouts, gussets, or different sized major flaps. This presents the problem, however, of effecting the folding of the lower, major flap beneath the guide while the upper flap is moved above the guide. Therefore, a need exists for a method and apparatus for folding the lower, major flaps of certain designs of sleeve-type cartons, including those having restricted access to the lower, major flaps, so that the lower flaps pass below a guide as the carton moves continuously downstream on the carton conveyor.
While the present invention is suited for use in continuous motion packaging machines as a flap folding assembly and method, it is adaptable to other applications in which a workpiece is contacted using a vacuum cup, and moved into another position. As a flap folding assembly and method, the present invention includes an apparatus positioned along the carton conveyor, and actuated in timed relationship with the downstream movement of the cartons to contact a carton flap and to move the carton flap into a desired position. One embodiment of the present invention comprises a flap folder positioned beneath the carton conveyor. The flap folder includes an upstanding arm which supports a vacuum cup that faces upwardly, toward the carton conveyor and the carton blank supported by the conveyor. The arm is moved so that the cup passes in a circular path toward and away from the conveyor and the transported cartons. The vertical arm is fixed to a horizontal crank link assembly. The arm and crank link assemblies are supported by shafts extending from spaced gears which are driven in timed relationship with the carton conveyor. The gears can be driven by a power takeoff from the main machine drive, or can be driven by a servo motor which receives a drive signal from the machine control computer.
Typically, two flap folder assemblies spaced on each side of the conveyor are utilized together in order to contact opposite ends of a carton carried transversely by the carton conveyor. The individual flap folder assemblies of a pair of assemblies are operated in unison, with one or more drive mechanisms turning the respective gears of each assembly so that the vacuum cups are positioned to contact opposite ends of the carton simultaneously. The pair of flap folding assemblies also can be driven from a single telescoping spline shaft, to permit simultaneous driving of the gears of the respective assemblies, and to allow the adjustment of the spacing between the opposed assemblies. This permits the flap folder assemblies to be used on packaging machines which are laterally adjustable to process different sizes or configurations of article groups.